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scitech.au.dk - News feedTYPO3 - get.content.righthttp://blogs.law.harvard.edu/tech/rssMon, 19 Nov 2018 13:02:00 +0100A bigger nose, a bigger bang: size matters for echolocating toothed whaleshttp://scitech.au.dk/en/about-science-and-technology/current-affairs/news/show/artikel/a-bigger-nose-a-bigger-bang-size-matters-for-echolocating-toothed-whales/
Whales, dolphins, and porpoises have all evolved to use similar narrow beams of high intensity...Trying to find your lunch in the dark using a narrow flashlight to illuminate one place at a time may not seem like the most efficient way of foraging. However, if you replace light with sound, this seems to be exactly how the largest toothed predators on the planet find their food.

A paper out this week in the journal Current Biology shows that whales, dolphins, and porpoises have all evolved to use similar narrow beams of high intensity sound to echolocate prey. Far from being inefficient, this highly focused sense may have helped them succeed as top predators in the world's oceans.

32 million years ago, the ancestors of toothed whales and baleen whales diverged as the ancestors of toothed whales – including dolphins, porpoises and sperm whales - evolved the ability to echolocate; to send out sound pulses and listen for the returning echoes from objects and prey in their environment.

This new sense allowed these animals to navigate and find food in dark or murky waters, during the night, or at extreme depths. Since then, this evolutionary step has allowed these animals to occupy an amazing diversity of habitats, from shallow freshwater rivers to the great ocean deeps.

A bigger nose, a bigger bang

The new study, led by Frants Havmand Jensen at the Aarhus Institute of Advanced Studies in Denmark, sheds light on how toothed whales adapted their sonar abilities to occupy different environments. He found that as animals grew bigger, they were able to put more energy into their echolocation sounds – but surprisingly, the sound energy increased much more than expected.

“Normally, organs tend to grow proportionally to the rest of the body, but as echolocating whales became larger, their sound generating structures started taking up more and more of the body,” said Professor Peter Teglberg Madsen of Aarhus University who co-authored the study.

The pinnacle of this evolutionary push is the sperm whale, where the nose used to generate and focus sonar pulses can make up as much as one-third of the body of adult males.

A narrow beam brings prey into focus

This work was funded by AIAS-COFUND fellowships from Aarhus Institute of Advanced Studies under the EU’s FP7 program (agreement no. 609033). Further support from the Danish National Research Foundation and the Carlsberg Foundation is acknowledged.

While size has a big influence on how loud echolocation signals are, animals of all sizes from 1.5m harbor porpoises to 16m sperm whales used a consistently narrow biosonar beam to inspect their surroundings, akin to using a narrow-beam flashlight to search for food in the dark.

“This is really similar to how our own vision works - we see best in just a narrow field of view which we turn towards whatever we want to look at,” said Dr. Mark Johnson from University of St. Andrews, a co-author of the study. These narrow sonar beams may help animals make sense of complex environments with lots of echoes”.

Using a narrow sonar beam has other advantages as well. “focusing the sound energy in one direction also helps increase the range at which prey can be detected and thus could lead directly to higher foraging rates – provided the beam doesn’t get too narrow,” added Jensen.

Read the study in Current Biology here

Contact:

]]>Public / mediagammelby@au.dkThu, 15 Nov 2018 11:47:00 +0100Massive impact crater from a kilometre-wide iron meteorite discovered in Greenlandhttp://scitech.au.dk/en/about-science-and-technology/current-affairs/news/show/artikel/massive-impact-crater-from-a-kilometre-wide-iron-meteorite-discovered-in-greenland/
An international team lead by researchers from University of Copenhagen and Aarhus University have...The crater measures more than 31 km in diameter, corresponding to an area bigger than Paris, and placing it among the 25 largest impact craters on Earth. The crater formed when a kilometre-wide iron meteorite smashed into northern Greenland, but has since been hidden under nearly a kilometre of ice.

"The crater is exceptionally well-preserved, and that is surprising, because glacier ice is an incredibly efficient erosive agent that would have quickly removed traces of the impact. But that means the crater must be rather young from a geological perspective. So far, it has not been possible to date the crater directly, but its condition strongly suggests that it formed after ice began to cover Greenland, so younger than 3 million years old and possibly as recently as 12,000 years ago – toward the end of the last ice age,” says Professor Kurt H. Kjær from the Center for GeoGenetics at the Natural History Museum of Denmark.

Giant circular depression

The crater was first discovered in July 2015 as the researchers inspected a new map of the topography beneath Greenland's ice-sheet. They noticed an enourmous, but previously undetected circular depression under Hiawatha Glacier, sitting at the very edge of the ice sheet in northern Greenland.

"We immediately knew this was something special but at the same time it became clear that it would be difficult to confirm the origin of the depression," says Professor Kjær.

In the courtyard at the Geological Museum in Copenhagen just outside the windows of the Center for GeoGenetics sits a 20-tonne iron meteorite found in North Greenland not far from the Hiawatha Glacier.

"It was therefore not such a leap to infer that the depression could be a previously undescribed meterorite crater, but initially we lacked the evidence," reflects Associate Professor Nicolaj Krog Larsen from Aarhus University.

The crucial evidence

Their suspicion that the giant depression was a meteorite crater was reinforced when the team sent a German research plane from the Alfred Wegener Institute to fly over the Hiawatha Glacier and map the crater and the overlying ice with a new powerful ice radar. Joseph MacGregor, a glaciologist at NASA, who participated in the study and is an expert in ice radar measurements adds:

"Previous radar measurements of Hiawatha Glacier were part of a long-term NASA effort to map Greenland’s changing ice cover. What we really needed to test our hypothesis was a dense and focused radar survey there. Our colleagues at the Alfred Wegener Institute and University of Kansas did exactly that with a next-generation radar system that exceeded all expectations and imaged the depression in stunning detail. A distinctly circular rim, central uplift, disturbed and undisturbed ice layering, and basal debris. It’s all there."

In the summers of 2016 and 2017, the research team returned to the site to map tectonic structures in the rock near the foot of the glacier and collect samples of sediments washed out from the depression through a meltwater channel.

"Some of the quartz sand washed from the crater had planar deformation features indicative of a violent impact, and this is conclusive evidence that the depression beneath the Hiawatha Glacier is a meteorite crater, " says Nicolaj K. Larsen.

The consequences of the impact on the Earth’s climate and life

Earlier studies have shown that large impacts can profoundly affect Earth’s climate, with major consequences for life on Earth at the time. It is therefore very reasonable to ask when and how and this meteorite impact at the Hiawatha Glacier affected the planet.

“The next step in the investigation will be to confidently date the impact. This will be a challenge, because it will probably require recovering material that melted during the impact from the bottom of the structure, but this is crucial if we are to understand how the Hiawatha impact affected life on Earth”, concludes Professor Kjær.

]]>Public / mediagammelby@au.dkWed, 14 Nov 2018 10:48:00 +0100DKK 30 million for high-tech electron microscopes for research in molecular cell biologyhttp://mbg.au.dk/en/news-and-events/news-item/artikel/dkk-30-million-for-high-tech-microscopes-for-research-in-molecular-cell-biology/
The Minister for Higher Education and Science has approved funding for three new research...Public / mediacts@au.dkThu, 08 Nov 2018 13:16:00 +0100Researches develop new protein for prevention of influenza virus infectionhttp://mbg.au.dk/en/news-and-events/news-item/artikel/researches-develop-new-protein-for-prevention-of-influenza-virus-infection/
An international research team has developed a new protein drug which has the potential to be used...Public / mediacts@au.dkFri, 02 Nov 2018 10:18:00 +0100New insight into the mechanism of the drug against sclerosis and psoriasishttp://mbg.au.dk/en/news-and-events/news-item/artikel/nyt-indblik-i-mekanisme-for-laegemiddel-mod-sklerose-og-psoriasis/
A multidisciplinary research team at Aarhus University has provided fundamental new insight into...Public / mediacts@au.dkThu, 01 Nov 2018 08:56:00 +0100Aarhus University new partner in major European innovation network in the food sectorhttp://scitech.au.dk/en/about-science-and-technology/current-affairs/news/show/artikel/aarhus-university-new-partner-in-major-european-innovation-network-in-the-food-sector/
Aarhus University has been appointed as a new partner in the EIT Food consortium. The EIT Food...The English translation will be available as soon as possible.

]]>Public / mediaamsiem@au.dkThu, 01 Nov 2018 13:26:00 +0100New centre leader at iFOODhttp://ifood.au.dk/currently/news/nyhed/artikel/new-centre-leader-at-ifood/
As of November 1, 2018, Milena Corredig is appointed as new Centre Leader for the iFOOD Aarhus...Public / mediaStaffcts@au.dkThu, 01 Nov 2018 13:05:00 +0100Jørgen Ellegaard Andersen wins € 10 million ERC Synergy Granthttp://scitech.au.dk/en/about-science-and-technology/current-affairs/news/show/artikel/joergen-ellegaard-andersen-vinder-10-mio-euro-erc-synergy-grant/
The European Research Council (ERC) has granted an ERC Synergy Grant of 10 million Euros to the... “ReNewQuantum” is a new approach to Quantum Theory and the main idea behind it takes its origin in the research agenda of QGM; a DNRF Center of Excellence led by Jørgen Ellegaard Andersen at the Department of Mathematics at Aarhus University.

However, where QGM with great success has focused on certain specific and special quantum theories, “ReNewQuantum” is aimed at Quantum Theory as a whole. The project proposes a scheme, which provides explicit recursive schemes to compute quantum corrections to all orders; it gives exact results by using all non-perturbative corrections and as something fundamentally new, it is based on advanced geometry and topology.

A new approach to Quantum Theory

ERC Synergy27 research groups across Europe have won highly-coveted ERC Synergy Grants in this call. This funding - maximum € 10 million per project - enables groups of two to four lead researchers to bring together complementary skills, knowledge and resources to jointly address research problems at the frontiers of knowledge. The grants are part of the EU's research and innovation programme, Horizon 2020 and the most prestigious grants due to its size and high requirement of research excellence.

“It is a fantastic opportunity to solely concentrate on this fascinating area between mathematics and physics for a sustained period of time”, says Jørgen Ellegaard Andersen.

He explains, that where quantum mechanics has a sound mathematical foundation, this is still lacking for Quantum Field Theory, certainly for theories as complex as the standard model of elementary particle physics and also for string theory, which is the current best candidate for quantum gravity.

“On the mathematical side, functional analysis has had a close interaction with Quantum Theory since its creation some hundered years ago. It is only during the last four decades that we have seen very successful applications of techniques from Quantum Theory in physics applied to predict deep conjectures in geometry and topology. With “ReNewQuantum”, we will reverse the stream and apply very advanced geometric and topological techniques to build a new approach to Quantum Theory, says Jørgen Ellegaard Andersen and adds:

“This is of course a grand endeavor and it will surely take the full synergetic strength of the four PI’s and the associated research teams”.

According to the ERC reviewers and the review panel, it is a splendid team.

“The PIs leading the project are world class scientists in Mathematical Physics, who together constitute a synergic team with the highest potential”, concludes the review panel.

The twelve reviewers all rated the proposal with the highest rating possible, “Outstanding”. Here is a small selection of the comments:

“This is a superb team. It is hard to imagine a stronger one”.

“It is difficult to imagine a better suited ensemble of researchers for the proposed project”.

“Each PI has had and continues to have brilliant achievements. They have the bold imagination, and the deep understanding of the state of the art, to combine their diverse skills to achieve something of the highest scientific importance”.

The four principal investigators are honored by the fine words from the reviewers and eager to get started:

“We are very excited and cannot wait to begin the project. With “ReNewQuantum”, our proposed transformational research is as first mover, to employ advanced geometric and topological tools in order to include all non-perturbative contributions. Even though they are typically exponentially small, they are still absolutely essential in order to get exact results and further, they can provide better numerical approximations in many cases”, says Jørgen Ellegaard Andersen.

About Jørgen Ellegaard Andersen and QGM Jørgen Ellegaard Andersen is professor and director of Centre for Quantum of Moduli Spaces (QGM), Department of Mathematics, Aarhus University. QGM was established in 2009 as a Center of Excellence funded by the Danish National Research Foundation (DNRF). The research objective is to address fundamental mathematical problems at the interface between geometry and theoretical physics. QGM hosts a strong team of high profile, internationally acclaimed researchers, and with the continuous generation of groundbreaking results, the Centre together with its international collaborators are recognized throughout the mathematics community worldwide as one of the leading research institutions in its research field.